The phrase "a key issue when" is correct and usable in written English.
It can be used to introduce an important topic or concern that arises in a specific context or situation.
Example: "A key issue when discussing climate change is the impact of human activity on natural ecosystems."
Alternatives: "a crucial factor when" or "an important consideration when".
Memory requirement is a key issue when servicing more number of nodes in a heterogeneous environment.
Feature quality evaluation is a key issue when designing an algorithm for feature selection.
The determination of geochemical fractions of heavy metals (HM) in soils is a key issue when studying their mobility.
Without manual oversight of the complete dataset, a key issue when building algorithms for this purpose is their accuracy.
Time studies consist in measuring repetitive work cycles; therefore, determining their structure is a key issue when planning measurements.
The vocational competence of the teachers is a key issue when the transforming of the drawings must match the reality.
Shared language was an identified key issue when approaching violence with the Somali born woman.
The measurement of malfunctions of pathways with a phenotype change, e.g., from normal to diseased, is the key issue when applying enrichment analysis on a pathway.
The measurement of dysfunctions of pathways during a phenotype change, e.g., from normal to diseased, is the key issue when applying enrichment analysis for pathway or other functional gene set.
Chafee, the former Democratic governor of Rhode Island, brought up this key issue when he announced his quixotic presidential bid to a half-empty room in the soulless suburb of Arlington, Virginia.
In terms of rights, it seems to me, the key issue when considering the involvement of 15-year-olds and over in military activity is whether they are volunteers or not.
